Buzzword alert, buzzword alert. "Counterfactual," as in, counter to fact. As in, not true. As in, a lie. What if the world were otherwise? What if Donald Trump weren't the nominee?
1) Would the Republican platform be different? Well, remember how John McCain was a pro-immigration reform type of guy? Yeah, then in 2008, he had to run on this:
So, replace Trump with another candidate. Would the "counterfactual" of a different candidate lead to a different platform? Probably not.
That leads us to the second part of the counterfactual.
2) Would another candidate do better in the polls? Almost certainly. I'm a statistician, so I won't say anything with absolute certainty, but Trump is underperforming. Fence/wall, same diff. Romney ran on a self-deportation thing, Trump is all about deportation, same diff. What makes Trump different? Not policy. That's the point. The predictive models, like Abramowitz's "Time for a Change" model, give the Republicans an edge in a year with two previous Democratic victories and only tepid economic growth.
During the DNC, Khizr Khan, muslim immigrant and father of a fallen veteran, harshly criticized Trump. The smart move for a presidential candidate? Ignore it. Trump, however, is a moron with no self control, leading to a week-long feud with the grieving parents of a war hero, 'cuz that's smart.
What's important here isn't the Khan story. What's important is that we are having a conversation about immigration and the Republican Party, not because immigration, as a policy issue is destroying the Republican Party via Trump, but because the Republican Party nominated Donald Trump. Despite the fact that Donald Trump's policy platform connects directly to McCain and Romney with respect to immigration, he is underperforming relative to them. In the counterfactual case of a Jeb Bush/Marco Rubio/Scott Walker/Any Republican Other Than Trump nomination, this wouldn't be a discussion. This isn't about a party facing a structural crisis. This is a story about a party with a lousy nominee. Is the growing Latino population an issue for the Republican Party? Sure. But, as I've been saying, demography is not destiny. Trump is just a lousy nominee.
And hey, look! I mentioned Khizr Khan without making a Star Trek reference! Must... not... post... clip...